LIASSIC DINOSAURS. 93 



mandible, accompanying the movement of that side of the head, has been pushed 

 so far below the left ramus as to have its inner side brought into view below that 

 of the left side of the skull. 



The occipital conforms to the Lacertian type (PI. 60, fig. 2, 4), in the pro- 

 portions and direction of the par-occipital ; this process is long, narrow, straight, 

 directed outwards, compressed from before backward, and slightly expanded at 

 the extremity, which is applied to the back part of the mastoid and tympanic at 

 the junction of those bones. It has been slightly displaced, its end appearing 

 on the left side at 4, PI. 45, with matrix intervening between it and the tympanic 

 (28). A part of the exoccipital which projects backward to contribute to the 

 formation of the condyle is exposed near the mass of matrix, including the atlas 

 vertebra and nuchal dermal bones. 



The cranial part of the skull, posterior to the orbits, is shorter in proportion 

 than in the lizards, and resembles, in this respect, that of the Iguanodon (PI. 

 49, fig. 9) and crocodiles. The parietal is short, and bifurcate behind, as in 

 lizards. The body of the bone, or part between the temporal foss«, is subcom- 

 pressed where it forms the smooth, concave, inner sides of those depressions, 

 which do not meet above, but are separated by a narrow, flat tract ; this might 

 be converted into a ridge in older individuals. The fore part of the parietal 

 slightly expands where it is overlapped by the frontals. Bach hind branch of 

 the parietal extends outward and a little backward ; its pointed end is obliquely 

 overlapped anteriorly by the mesial branch of the mastoid, completing therewith 

 the hind boundary of the temporal fossa. The crushed and dislocated state of 

 the calvarium along its middle line does not permit the usual evi^lence of a 

 foramen parietale to be detected, but the appearances are against such perforation 

 being present. This foramen is not constant in modern lizards ; the Scelidosaurus 

 may agree with Cydodus and Tejus in this respect. The parietal bone, as a whole, 

 plainly accords with the lacertian, not with the crocodilian, type of that bone. 



The mastoid (8) is a triradiate bone, forming the upper and hinder angle of the 

 cranium, from which one ray passes mesiad to join the parietal (7), a second ray 

 forward to join the post-frontal (PI. 46, 12), and a third ray downward (PI. 45, 8), 

 to join the tympanic (2s). A fracture of the body of the mastoid, by which he 

 anterior branch is broken away on the left side, exposes a cancellous cavity, 

 probably forming part of the organ of hearing. 



The two halves of the mid-frontal (PI. 47, ll) have been separated along the 

 medial line, and the right half depressed. The separation appears to have been 

 at a suture, as is certainly the case with the nasal bones ; the medial margin of 

 three fourths of the left frontal show the jagged, sutural character. I conclude, 

 therefore, that the mid-frontal was divided, as in Iguanodon (PI. 49, fig. 9, 11), 

 and as in Varanus and Lacerta proper ; and that it was not a single bone, as in 



